PEG-Supported Pyridylthioesters for Racemization-Free Amide Synthesis: a Reagent That Allows Simultaneous Product Formation and Removal From The Polymer

Pyridylthioesters anchored to a modified poly(ethylene glycol) of Mw 5000 Da have been prepared in high yields. The thioesters were employed as a convenient starting materials for the liquid-phase synthesis of various enantiomerically pure amides. This new methodology allowed to perform simultaneously the reaction with the poly(ethylene glycol)-supported reagent and the traceless removal of the final product from the polymer support in a single step. The products were obtained in high yield and purity.